How Memory Functions: Learn It 3—Explicit and Implicit Memories

Long-Term Memory: Explicit and Implicit

There are two types of long-term memory: explicit and implicit. Understanding the difference between explicit memory and implicit memory is important because aging, brain trauma, and certain disorders can impact explicit and implicit memory in different ways.

explicit memory

Explicit memories are those we consciously try to remember, recall, and report. For example, if you are studying for your chemistry exam, the material you are learning will be part of your explicit memory. Explicit memory is sometimes referred to as declarative memory because it can be put into words.

Explicit memory is divided into episodic memory and semantic memory.

A diagram consists of three rows of boxes. The box in the top row is labeled “long-term memory;” a line from the box separates into two lines leading to two boxes on the second row, labeled “explicit memory” and “implicit memory.” From each of the second row boxes, lines split and lead to additional boxes. From the “explicit memory” box are two boxes labeled “episodic (events and experiences)” and “semantic (concepts and facts).” From the “implicit memory” box are three boxes labeled “procedural (How to do things),” “Priming (stimulus exposure affects responses to a later stimulus),” and “emotional conditioning (Classically conditioned emotional responses).”
Figure 1. There are two components of long-term memory: explicit and implicit. Explicit memory includes episodic and semantic memory. Implicit memory includes procedural memory and things learned through conditioning.

episodic memory

Episodic memory is information about events we have personally experienced (i.e., an episode). For instance, the memory of your last birthday is an episodic memory. Usually, episodic memory is reported as a story. The concept of episodic memory was first proposed about in the 1970s (Tulving, 1972). Since then, Tulving and others have reformulated the theory, and currently scientists believe that episodic memory is memory about happenings in particular places at particular times—the what, where, and when of an event (Tulving, 2002). It involves the recollection of visual imagery as well as the feeling of familiarity (Hassabis & Maguire, 2007).

semantic memory

The other type of explicit memory is called semantic memory. It is knowledge about words, concepts, and language-based knowledge and facts. Semantic memory is typically reported as facts. Semantic means having to do with language and knowledge about language. For example, answers to the following questions like “what is the definition of psychology” and “who was the first African American president of the United States” are stored in your semantic memory.

Implicit Memory

In contrast with explicit memories, implicit memories are long-term memories that we don’t really have to think about.

implicit memory

Implicit memories are long-term memories that are not part of our consciousness. Although implicit memories are learned outside of our awareness and cannot be consciously recalled, implicit memory is demonstrated in the performance of some tasks (Roediger, 1990; Schacter, 1987).

 

Implicit memory has been studied with cognitive demand tasks, such as performance on artificial grammar (Reber, 1976), word memory (Jacoby, 1983; Jacoby & Witherspoon, 1982), and learning unspoken and unwritten rules (Greenspoon, 1955; Giddan & Eriksen, 1959; Krieckhaus & Eriksen, 1960).

 

Implicit memories are like a program running in the background, and you are not aware of their influence. Implicit memories can influence observable behaviors as well as cognitive tasks. In either case, you usually cannot put the memory into words that adequately describe the task.

There are several types of implicit memories, including procedural, priming, and emotional conditioning.

Implicit procedural memory stores information about the way to do something, and it is the memory for skilled actions, such as brushing your teeth, riding a bicycle, or driving a car. You were probably not that good at riding a bicycle or driving a car the first time you tried, but you were much better after doing those things for a year. When you first learned to do these tasks, someone may have told you how to do them, but everything you learned since those instructions that you do without thought and cannot readily explain to someone else as the way to do it is implicit memory.

Implicit priming is another type of implicit memory (Schacter, 1992). During priming exposure to a stimulus affects the response to a later stimulus. Stimuli can vary and may include words, pictures, and other stimuli to elicit a response or increase recognition. For instance, some people really enjoy picnics. They love going into nature, spreading a blanket on the ground, and eating a delicious meal. Now, unscramble the following letters to make a word: AETPL.

What word did you come up with?

Chances are good that it was “plate.” Had you read, “Some people really enjoy growing flowers. They love going outside to their garden, fertilizing their plants, and watering their flowers,” you probably would have come up with the word “petal” instead of plate.

Do you recall the earlier discussion of semantic networks? The reason people are more likely to come up with “plate” after reading about a picnic is that plate is associated (linked) with picnic. Plate was primed by activating the semantic network. Similarly, “petal” is linked to flower and is primed by flower. Priming is also the reason you probably said jelly in response to peanut butter.

Implicit emotional conditioning is the type of memory involved in classically conditioned emotion responses (Olson & Fazio, 2001). These emotional relationships cannot be reported or recalled but can be associated with different stimuli. For example, specific smells can cause specific emotional responses for some people. If there is a smell that makes you feel positive and nostalgic, and you don’t know where that response comes from, it is an implicit emotional response. Similarly, most people have a song that causes a specific emotional response. That song’s effect could be an implicit emotional memory (Yang, Xu, Du, Shi, & Fang, 2011).

 

Is it possible to have a perfect memory? Eidetic memory refers to the ability to see an object for a few minutes after it is no longer present and photographic memory refers to the ability to recall pages of text or numbers in great detail. They are often used interchangeably, but eidetic memory is reported to occur in a small number of people, typically children, and is generally not found in adults, while true photographic memory has never been demonstrated to exist.

Another type of super memory is superior autobiographical memory, also known as hyperthymesia (HSAM). This is an incredibly rare condition (under 70 people having been identified with the condition) where a person can remember what they were wearing, what they did, what the weather was like, and everything else they experienced in their past (usually starting in late childhood or adolescence).

A photograph shows Marilu Henner.
Figure 2. American actress Marilu Henner, best known for the television show Taxi, has superior autobiographical memory. (credit: Mark Richardson)

This SciShow Psych video explains more about hyperthymesia and demonstrates that while it does result in astonishing memory feats, it does not work like a perfect record player and memories can still be misconstrued during retrieval.

Think about something you have learned that is now in your procedural memory. Reflect on how you learned this information.

Can you think of something you learned in high school that is now in your semantic memory?